SERVER-12799 Disable balancer in aggregation/testshard1.js
Revert "SERVER-12650 make syncSourceFeedback's oplogreader effectively single threaded"

This reverts commit 617b4896241649e2a3203e33e5901907790002b5.
SERVER-12650 locking to protect the fallback oplogreader
increase awaitReplication time in slowWeekly/replsets_prefetch_stress.js since it is timing out on windows builders
SERVER-12797 Javascript lint
SERVER-12797 speed up update_yield1.js by not trying with too-small data sizes
SERVER-12797 detect getlasterror op in update_yield1.js.
BUMP 2.6.0-rc0
post 2.6.0-rc0
SERVER-12804:smoke.py small_oplog improvements
SERVER-10026 remove most remaining QUERY_MIGRATION tags
SERVER-12826 count10.js test improvements
SERVER-12822 added a multiversion test to verify oplog entries and multivesion compatibility of new updates
SERVER-12804 Revert smoke.py log message change causing test failure